In-situ hydrothermal synthesis of a novel morphology daisy shape nickel cobalt oxide films for high performance supercapattery

Abstract

NiCo2O4 is widely used in traditional battery and supercapattery due to its extremely high capacitance value. Herein, the in-situ hydrothermal method has been optimized in order to utilize its own charge storage capacity. NiCo2O4 nanosheet thin films with four different morphologies (wrap, neuron, daisy, and tablet shape) are synthesized on Ni foam surface without mechanical stress damage. In the absence of interference from conductive agents and binders, these NiCo2O4 nanosheet thin films with different morphologies provide various conducive channels for charge transfer and more sites for redox reactions achieve better energy storage properties. Particularly, the daisy shape NiCo2O4 nanosheets have the highest capacity (C g−1) of 972.5 (2 M KOH) at 1 A g−1 comparing to others. Furthermore, after subjecting it to 1800 cycles of cyclic stability testing at 40 A g−1, its capacity (C g−1) remarkably increased to 1433.5. In addition, using the daisy shape NiCo2O4 nanosheets thin film and activated carbon, a supercapattery is assembled. The results exhibit that it has an impressive performance of 39.8 W h kg−1 at 750 W kg−1 comparing to other works, which demonstrates that our in-situ hydrothermal synthesized daisy shape NiCo2O4 nanosheet has significant potential in the field of energy storage.